Leetcode 112. Path Sum

Question

Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the given sum.

For example:

Given the below binary tree and sum = 22,

5
/ \
4   8
/   / \
11  13  4
/  \      \
7    2      1

return true, as there exist a root-to-leaf path 5->4->11->2 which sum is 22.

Code

public boolean hasPathSum(TreeNode root, int sum) {
if (root == null) {
return false;
}

if (root.left == null && root.right == null && sum == root.val) {
return true;
}

return hasPathSum(root.left, sum - root.val)
|| hasPathSum(root.right, sum - root.val);
}